Improvement in grinding and pulverizing acid phosphates



G. P. WILSON. GRINDING AND YPULVERIZING ACID PHOSPHATES.

No. 75,333. I Patented Mar. 10, 1868,

WITNESSES.

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gfliitlt 131m gau t f GEORGE F. WILSON, OF EAST PROVIDENCE, RHODE ISLAND.

Letters Patent No. 75,333, dated Marc/z 10,- 1 868.

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TO ALL WHOM IT MAY CONCERNr Be it known that I, GEORGE F. WILSON, of East Providence, in the countyof Providence, and the State of Rhode Island, have invented a new and improved Method-of Grinding Horsfordis Acid Phosphate of Lime; and I do hereby declare that tho followingisa full and exact description thereof, reference being had to the ocean pnnying drawings and to the letters of reference mark-ed thereom;

. The object of my invention is to reduce to powder the acid-phosphate, which, while brittle atcommon tom-- peratures, is rendered adhesive by the heat producedin the use of ordinarymillstones, and, sticking to the stones, soon cements them together and arrests the grinding. I. have experimented withthe conicaliron mill, with polished cylinders, and'burr, and other stones, .b'ut allhave failed,;becausc'of the heat developed in continuous .pulverization.

The nature ofthe invention consists in the interrupted crushing of the granulated acid phosphate, by which time is given for the powder to cool. The device by whichthe object is effected consists of a bed-stone on which, standing on their curved edges like wagon-wheels, are twoshort stone cylinders, attiiched to the opposite ends. of an axle, which axle passes through anupright s'haft midw'ay between the two stone cylinders. By revolving the upright shaft, the stone cylinders are swept ronndat the extremities of the axle, describing orbits having a radius equal to half the lengthof the axle, and producing an eii'ect compoundedo'f the pressure of a rolling cylindor on a plane surface,.and the slipping of a curved surface on a plane surface.

These motions slowly reduce the gran-uiated'a'cid to powder, while the ti-ine required for the wheel to revolve allows the heatdeveloped by the pressure and pulveriz-ation'to dissipate, so that-the acid does not beoomehot enough to be rendered adhesive, as is thekcase in grinding between ordinary millstones. As the stones revolve a scraper follows, stirring up theacid and increasing thev cooling efl'eot.

The accompanying drawing illustrates the relations of the. partsandtheir mode of operation.

a a and b b are short stone cylinders, stan ding on their curved surfaces. 0 c is the bed-stone. d d is the axle on which the stone cylinders revolve. .e-e' is-the-uprightshaft, resting on the bed-stone at e, having its oblique oil-tube It and its leathern hood 2;. Through theshat'te e-passes the axle d d; ff is the line of shafting, communicating motion to the upright shaft by bevel-wheels, and-through it-to the axle d cl, and the stone cylinders a-a and 6 b. I

Thepractical operation of the mill'is as follows: Through the chuteg the dried granulated acid is fed from a hopper above, as received from the drying-chamber, described in my application for a patent of even date herewith, of which held auniform supply is-maintained by the ji'gger j attached to the chute. The acid falling, as used in grain-mills,-between the cylindersppasses under them, and is crushed and rubbed by them to powder. The parts of the surface of the stones, interior to what may be the point of continuous simple contact without sliding, slipbackward, while those exterior'to it slip fc rward,at the same time imparting a total centrifugal and forward motionto the powder, oarryingit before and beyond the stones against the casing m mm" m' on one side ofwhich, at a, there is an overflow, where-thepowdered acid leaves the bed-stone to be taken up by clcvators 7t 1t and carried to the bolt. The coarser particles separated by the bolt are returned by elevators to be recrushed. The cylinders may be faced with iron, or wholly .of' iron, the object being to gain an interval oi time between successive crushing'eii'ects or impacts in'thcprolcese bfigrinding. v

What I claim, and desire tosccure by Letters Patent of the United States, is-

1. An improved process of'disintegrating and pulveriz ing the dried and granulated mixture of acid phosphate of lime and farinaccous matters, substantially in the manner and for the purposes described, whcrebythc heating thereof is prevented, by causingthe pnlveriaing action of the mill to be applied to any particular portion of the mixture to be at intervals, which allow time-for cooling between successive. impacts.

2. I also claim the application of the above-described apparatus to the pulverization of acid phosphate of lime mixed with farinaceous matters, substantially as above described.

' GEO. F. WILSON.

Witnesses WILLIAM Huncn, Wmsrow WARREN, Jr. 

